Blood-flow to the brain affects how the brain functions and therefore how the individual works. I have been studying physiological factors that affect these blood-flows. I have found, clothing can have a marked effect. In particular tighter items such as bras and trousers. To optimize the blood flows (and ulitmately oxygen to the brain) uplifting bras are preferable to normal, tight leggings as opposed to frumpy skirts and you might as well thrown on some tarty make-up whilst you are about it.